It is known that conventional wheels for bicycles essentially comprise a rim carrying the tire which rolls on the ground, a hub rotatable on a pin fixed to the bicycle frame, and a plurality of spokes connecting the rim to the hub. More precisely, such wheels are composed of a group of elements comprising: a rim for the tire, carrying rest bushings for the anchorage and tension nipples; a series of internally threaded nipples; a series of spokes, anchored at one end with a riveted head to either of the two flanges of the hub, and having the opposite end threaded to be stretched by the rotary and screwing action of said nipples; and a hub having two flanges, with holes arranged over a circumference for inserting and fixing the spokes therein.
On wheels of this type - used in the cycling field for many years - several studies have been made to provide the wheel with a good capability to absorb impacts for the cyclist's comfort, with an adequate stoutness and with the greatest possible lightness, compatibly with the strength of the whole structure. Though resorting to all the technologies applicable in this field and to the classical or most modern and sophisticated materials, with low ratio between the weight and the mechanical characteristics, the possibilities of weight reduction are nevertheless few.
The problem of reducing the weight in these wheels - especially in those having to be mounted on racing and competition bicycles and in those designed for use by the ever increasing number of demanding sportsmen - is therefore still unsolved and it forms the object of greatest consideration by the designers and producers of bicycle wheels.
On the other hand, the traditional spoked wheels considered heretofore, offer a remarkable drag, which recent studies have proved to rapidly increase with speed, and the importance of which - disregarded up to a few years ago - now forms the object of the most careful consideration by the skilled in the art, in view of the even decisive influence which the aerodynamic behaviour of the wheels can have during races and competitions, particularly those in which high speed limits are reached, even for a short while. It is known that, in order to improve this behaviour, various types of disk wheels have been realized, wherein the connection between the wheel hub and the rim is no longer obtained through spokes, but through a disk or through a pair of flat or curved walls (lenticular wheels). In wheels of this type produced up to date -almost always designed for special purposes or even for specific experiments - the problem of lightness has never been taken into account, as it often has no influence at all on the specific results having to be achieved, whereby said wheels are all rather heavy and anyhow far heavier than the ordinary spoked wheels, and this makes them totally inadequate for normal use.
It can therefore be said that the two problems currently more felt in the planning and construction of wheels for bicycles designed for sports use and especially competitions - namely the problem of obtaining combined stoutness and lightness of the wheel and the problem of obtaining a low drag - have up to date been faced separately and with conventional means; the first problem, by operating on a typical spoked wheel structure and by simply acting on the gradually improving properties of the materials available and on the more advanced techniques for their production, and the second problem, by adopting an original structure in its external configuration, but obtained without a rational consideration and, least of all, an accurate study of its responses to stresses, and sometimes even disregarding the requirements of strength and lightness.